Conventionally, a clip may be introduced into a body cavity through an endoscope to to grasp living tissue of a body cavity for hemostasis, marking, and/or ligating. In addition, clips are now being used in a number of applications related to gastrointestinal bleeding such as peptic ulcers, Mallory-Weiss tears, Dieulafoy's lesions, angiomas, post-papillotomy bleeding, and small varices with active bleeding.
Gastrointestinal bleeding is a somewhat common and serious condition that is often fatal if left untreated. This problem has prompted the development of a number of endoscopic therapeutic approaches to achieve hemostasis such as the injection of sclerosing agents and contact thermo-coagulation techniques. Although such approaches are often effective, bleeding continues for many patients and corrective surgery therefore becomes necessary. Because surgery is an invasive technique that is associated with a high morbidity rate and many other undesirable side effects, there exists a need for highly effective, less invasive procedures.
Mechanical hemostatic devices have been used in various parts of the body, including gastrointestinal applications. Such devices are typically in the form of clamps, clips, staples and tethers, which are able to apply sufficient constrictive forces to blood vessels so as to limit or interrupt blood flow. One of the problems associated with conventional hemostatic devices, however, is that many devices are not strong enough to cause permanent hemostasis.
Additionally, it may be difficult to progressively close a plurality of arms of a clip device. In particular, many clips comprise an open state where the plurality of arms are spaced apart from one another, wherein tissue may be positioned within the arms in the open state. Such clips further comprise closed states in which the arms are adjacent to one another, wherein the arms impose a compressive force upon the tissue in an effort to cause hemostasis. In some clips, a cannula is distally advanced over the arms to move the arms between the open and closed states. Generally, the clip is either in an open or closed state, but most clips cannot be incrementally closed, i.e., the first and second arms cannot be securely locked in any number of incremental positions.